Typically, the parameters on which an engine is operated are selected to account for variations in the fuel supplied to the engine and variations in the efficiency of the engine itself. In many instances, the engine's operation is sub-optimal, because the parameters are selected to maintain engine operation on the lowest of a range of fuel qualities and the worst of a range of engine conditions. For example, an engine may receive fuel with a high knock resistance at some point in its operation and fuel with a low knock resistance at another point in its operation, and must be able to operate on both. In another example, a newly commissioned engine is in top mechanical shape, but over time, build-ups in the combustion chambers and wear of the sealing surfaces reduce the engine's efficiency. The engine's operating parameters; however, are selected to operate the engine throughout its life span. Accordingly, they may be sub-optimal when the engine is new and sub-optimal near the end of Some engine systems have been configured to adjust the operating parameters to account for various factors that affect the engine's efficiency. There is a need for such type of engine systems that adjust the operating parameters to account for variations in fuel quality and engine condition.